Generally, a radio communication system of today comprises a radio access network and a number of communication devices. The radio access network is built up of several nodes, in particular, radio base stations. The primary task of a radio base station is to send and receive information to/from the communication devices within a cell served by the radio base station. In many cases, the base station runs 24 hours a day. Therefore, it is of particular interest and importance to ensure that the base station is operable predictably and reliably. The radio base station further comprises an enclosure, such as a cabinet, for housing circuitry, or electronic equipment, for performing different tasks of the radio base station. For example, the circuitry may comprise a power control unit, a radio unit, comprising a radio amplifier, a filtering unit for performing corresponding tasks.
Due to low efficiency in the radio amplifier of the radio base station, heat generated in the circuitry of the base station, in particular the radio unit, may not always dissipate naturally to a sufficiently high degree. Instead, heat is accumulated in the circuitry and the temperature of the circuitry increases. The increased temperature of the circuitry may decrease the performance of circuitry within the radio base station, e.g. the circuitry within the radio base station may fail. Consequently, unpredicted interruptions in operation of the base station may occur. This is clearly not desired.
Hence, as is known in the art, systems for cooling of heat generating equipment within a radio base station have been developed. These systems are sometimes referred to as climate systems or climate control systems for radio base stations.
According to a prior art technique for cooling of heat generating equipment, fans are used to circulate air through or over the heat generating equipment and through or over one side of a heat exchanger (i.e. an internal side within the enclosure). Moreover, further fans are used to force ambient air through or over the other side of the heat exchanger (i.e. an external side). The heat exchanger comprises a refrigerant that absorbs heat from the air, heated by the electronic equipment, at the internal side within the enclosure. As a result, a transition from liquid phase to gas phase of the refrigerant occurs. The portion of the heat exchanger that is located at the internal side within the enclosure is called evaporator. The gas is, by evaporation, forced to the external side of the heat exchanger, where it dissipates heat to ambient air. As a result, a transition from gas phase to liquid phase of the refrigerant occurs in the external side of the heat exchanger. The portion of the heat exchanger that is located on the external side is called condenser. At this stage, gravity forces the liquid to flow towards the evaporator. This kind of heat exchanger is generally denoted a thermosiphon. Further, a climate system needs to be equipped with some kind of temperature measuring device to help regulate the climate system.
An enclosure or cabinet of a predetermined size may be provided with different kinds of electronic equipment and in different amounts depending on particular demands from a user. Further, the amount of cables within cabinets that are heavily equipped may be considerable, and may therefore influence the movement of air to and from different parts of the cabinet. Accordingly, the amount of dissipated heat and the location of dissipated heat within a cabinet having a certain size and a certain climate system may vary substantially depending on the type of electronic equipment, its location within the cabinet as well as the amount of different electronic equipment. This may lead to temperature variations within the cabinet, which in turn leads to poor performance of the equipment. Therefore, in many prior art climate systems there is a problem with controlling the temperature within the cabinet.
As may be realized from the above, there is a need for improvement in the field of climate systems for radio network nodes, such as radio base stations. Particularly, there is a need for improvements in controlling the temperature within the cabinet, which cabinet is provided with electronic equipment and a climate system.